You do not need 1 for 1 because the vast majority of the engineering tasks are on items that are not catastrophic if they fail. It turn out that MCAS is a catastrophic system but was not certified as such. Whether this was an oversight or a devious scheme is yet to be determined
You don’t need 1:1 because many hours of engineering can be reviewed in 1 hour. It is idiotic to think that someone has to stand there and watch your every move, thought, or action to provide oversight.